HTP/PLA Hybrid Test 04-08-2021
This is a repeat of the 01-27-2021 test but with a 1/4" stainless steel mist injector with a 1.0 mm diameter orifice, a 3.0 mm fuel core wall thickness, L/D=12.5 (vs 2.0 mm, L/D=10.5 in 01-27 test), and 85% HTP (vs 90%). Combustion instabilities seem to be under control due to a higher pressure drop across the injector. The net positive thrust occurs at the end of the video corresponding to the erosion of the graphite nozzle throat from 3.6 mm to 5.2 mm. The increase in throat diameter reduces chamber pressure and increases mass flow rate resulting in a net positive thrust. Net positive thrust occurred for ~2 sec at a thrust of greater than 12 N. PLA fuel core segments were infused with potassium permanganate at high temperature and pressure.